A method for producing a 3-halo-1,2-benzisothiazole represented by the general formula (2): wherein R1 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 5 carbon atoms, a nitro group or a halogen atom, and X is a halogen atom, the method characterized by reacting a 1,2-benzisothiazol-3-one represented by the general formula (1): wherein R1 is the same group as the R1 defined in the above general formula (2), with a thionyl halide in a polar solvent. The 3-halo-1,2-benzisothiazole obtainable according to the method of the present invention is suitably used as production raw materials and the like for a medicament and the like.